Package logilab-common-0 :: Package 39 :: Package 0 :: Module tasksqueue
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Source Code for Module logilab-common-0.39.0.tasksqueue

 1  """Prioritized tasks queue 
 2   
 3  :organization: Logilab 
 4  :copyright: 2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved. 
 5  :contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr 
 6  """ 
 7  __docformat__ = "restructuredtext en" 
 8   
 9  from bisect import insort_left 
10  from Queue import Queue 
11   
12  LOW = 0 
13  MEDIUM = 10 
14  HIGH = 100 
15   
16   
17 -class PrioritizedTasksQueue(Queue):
18
19 - def _init(self, maxsize):
20 """Initialize the queue representation""" 21 self.maxsize = maxsize 22 # ordered list of task, from the lowest to the highest priority 23 self.queue = []
24
25 - def _put(self, item):
26 """Put a new item in the queue""" 27 for i, task in enumerate(self.queue): 28 # equivalent task 29 if task == item: 30 # if new task has a higher priority, remove the one already 31 # queued so the new priority will be considered 32 if task < item: 33 item.merge(task) 34 del self.queue[i] 35 break 36 # else keep it so current order is kept 37 task.merge(item) 38 return 39 insort_left(self.queue, item)
40
41 - def _get(self):
42 """Get an item from the queue""" 43 return self.queue.pop()
44
45 - def __iter__(self):
46 return iter(self.queue)
47
48 - def remove(self, tid):
49 """remove a specific task from the queue""" 50 # XXX acquire lock 51 for i, task in enumerate(self): 52 if task.id == tid: 53 self.queue.pop(i) 54 return 55 raise ValueError('not task of id %s in queue' % tid)
56
57 -class Task(object):
58 - def __init__(self, tid, priority=LOW):
59 # task id 60 self.id = tid 61 # task priority 62 self.priority = priority
63
64 - def __repr__(self):
65 return '<Task %s @%#x>' % (self.id, id(self))
66
67 - def __cmp__(self, other):
68 return cmp(self.priority, other.priority)
69
70 - def __eq__(self, other):
71 return self.id == other.id
72
73 - def merge(self, other):
74 pass
75